Bollywood star son Abhishek Bachchan, who plays father to real life dad Amitabh Bachchan in R Balakrishnan's upcoming movie Paa feels that it is a lifetime oppurtunity for him.

Bollywood star son Abhishek Bachchan, who plays father to real life dad Amitabh Bachchan in R Balakrishnan's upcoming movie Paa feels that it is a lifetime oppurtunity for him.

"This is a role of a lifetime. Very few actors get such an experience and opportunity... especially a son to play father to his own Paa . We are only and perhaps the first actor father-son duo to have played themselves in a role reversal," Abhishek told PTI in an interview.

He said that Paa , where Big B plays a 13-year-old boy suffering from progeria, a rare genetic disorder which accelerates ageing, is a simple, light hearted and happy film.

"Paa is not a film about progeria. It is a happy film about a father and his son and the sweet moments that they share," Abhishek said.

"The genetic disorder is just the unique backdrop of the film... just like 'Mili' where my mother (Jaya Bachchan) is suffering from a disease but the film was not about the illness," he said.

"There is a family in Kolkata where three children of a family suffer from progeria syndrome. But Balki did not want us to meet them and discuss their condition because it would have been very insensitive and intrusive," the Junior Bachchan said.